Bravo for Brassicas
The New Year is a time for resolutions and one of the most common is the vow to eat a more healthful diet. An easy and delicious way to do this is to include more brassicas, or members of the cabbage family, in your diet -- and your gardens. Homegrown broccoli, cabbage, cauliflower, Brussel's sprouts, kale, collards and kohlrabi make for delectable eating when picked fresh from the vegetable garden and served raw, roasted, lightly steamed or stir-fried. And they are all some of the most nutritious crops you can grow. Not only loaded with vitamins, minerals and fiber, cabbage family members are also especially high in the phytochemicals that act as antioxidants to protect against cancer, diabetes and heart disease. So plan now to include some of these "super-veggies" in your garden this spring.
The cabbage family clan, also known as cole crops, are all, surprisingly, variations on one species, Brassica oleracea. Selective breeding over hundreds of years has produced the variety of crops we now cultivate, including B. o. variety capitata (meaning "head") or cabbage, and B. o. variety acephala (meaning "without a head") or kale and collards. Chinese cabbages are brassicas too, but are different species (B. rapa) more closely related to turnips. While the timing of planting and their use in the kitchen may vary, all these relatives need similar cultural conditions. They all do best when grown in fertile, humus-rich soil in the cool (but not too cold) temperatures of spring and fall.
Broccoli and cabbage are probably the two most popular cole crops for home gardeners, both for their taste and versatility in the kitchen as well as their ease of cultivation.
While you can direct seed broccoli right in the garden, success is more assured if you start seeds indoors and transplant seedlings to the garden when they are large enough to better weather insects pests and outdoor temperatures. Start seeds 6 to 8 weeks before the last frost date in your area; transplant hardened off seedlings into the garden two weeks before the the last frost date. For a fall crop, sow seeds 10 to 12 weeks before the first fall frost date. Gardeners in mild winter climates can sow succession crops in the fall for harvest throughout the winter.
Broccoli is a heavy feeder so work a few inches of organic matter into the soil before planting. Soil pH between 6.0 and 7.2 is ideal. Space seedling 15-18 inches apart and set them slightly deeper than they were growing in the container, up to their first set of true leaves. Protect the stem of each plant with a cutworm collar. The simplest way is to wrap the seedling stem with 2- to 3-inch strips of newspaper. Cover the seedlings with a floating row cover to prevent damage from flea beetles and cabbage worms. If the temperature dips below 50 degrees for more than one night, add some extras layers of row covers to prevent chilling injury.
Get your broccoli off to a good start with a sidedressing of a soluble fertilizer about 2 weeks after transplanting and again just as the heads begin to form.
Broccoli is ready to harvest as soon as the head, which is actually a cluster of unopened flower buds, is of a usable size and has a deep green color. Cut the main head with a 2 inch stem, then check for the formation of smaller side shoots that will extend your harvest.
Growing rapini is a little different than growing heading broccoli. Direct sow as soon as the soil can be worked in the spring, spacing seeds 1-2 inches apart and thinning to 6 inches. Harvest this fast-maturing crop when stems are about a foot tall and flower heads about an inch across. For a fall crop, sow seeds in late summer and early fall, making succession plantings up until about 3 weeks before the first fall frost.
Like broccoli, cabbage is best started indoors and set into the garden as transplants. Start seeds in spring 6 to 9 weeks before the last spring frost, transplanting them to the garden 1 to 3 weeks before the last frost. Sow seeds for a fall crop about 12 weeks before the date of the first hard frost, transplanting them out about 6 weeks later. Space seedlings 12 to 24 inches apart, depending on the mature size of the variety you're growing.
Cabbage grows best with a steady supply of nutrients, so feed with a half-strength solution of soluble fertilizer at planting, then weekly for the next 3 weeks. Also be sure the developing plants have a steady supply of water; mulch the bed to conserve soil moisture.
As with broccoli, cutworms collars and row covers will help prevent pest problems. And be sure to give cabbage seedlings some extra protection if temperatures dip below 50 degrees for more than a day or two.
When cabbage heads are hard and firm and about the size of a softball, you can begin harvesting or let them mature to their full size. If you cut the heads of spring cabbage leaving as much stem as possible, several buds may begin to sprout at the cut. Cut off all but one and you'll harvest a second, smaller head of cabbage later in the season.
Unlike regular cabbage, Chinese cabbage does best if it's direct-seeded. Sow seeds as soon as the soil can be worked for a spring crop. Fall sown Chinese cabbage is often easier to grow, being less likely to bolt due to warm weather. Sow seeds 12 weeks before the first fall frost date. Harvest when young and tender by either cuting individual leaves or the entire head.
Question of the Month: Tiny Heads of Broccoli
Q: My broccoli only formed tiny heads. What went wrong?
A: When broccoli develops tiny heads, it's called "buttoning." This happens in response to stress on the plants, sometimes due to lack of water or nutrients, or too much competition from weeds. The most common cause, however, is exposure to overly cold temperatures when the plants are small. To prevent this problem, make sure your broccoli plants have fertile soil and consistent moisture throughout the growing season. Don't plant them too early-- wait until temperatures usually stay above 50 degrees. If the weather turns cold for more than a day or two after plants are in the garden, give them some protection with medium-weight row covers, plastic tunnels or some other form of insulation.